City Council hears flood mitigation options

The Ames City Council will have tough decisions to make when it comes to reducing the risk of flooding in the future.

The Ames City Council will have tough decisions to make when it comes to reducing the risk of flooding in the future.

The council was presented with three new flood mitigation alternatives at a special meeting Tuesday night.

The consultant who undertook the study, HDR Engineers Inc., presented a number of alternatives to the city in April. However, the council asked the firm to examine several combinations of the proposed solutions.

John Dunn, director of the Ames Water and Pollution Control Department, said the options presented to the council in the spring fell under three categories: storage, physical protection measures and non-engineered/non-structural.

The city commissioned HDR, of Des Moines, to analyze flood mitigation solutions for the city. The city called for the study in response to the flooding in 2010 that inundated South Duff Avenue and parts of the Iowa State University campus, including Hilton Coliseum.

The consultants have studied the city and its floodplain policies, and environmental factors in regard to flooding risk. They also have held a series of meetings and open houses.

The first option presented to the council Tuesday would be to lengthen the U.S. Highway 30 bridge and include work to reshape the Squaw Creek channel. That would have a construction cost of about $12.5 million and a “benefit/cost ratio” of 3.5, according to the report.

That ratio represents the estimated annual reduction in damage from flooding compared to the total annual cost of the project over 50 years. A ratio of more than one indicates the benefit outweighs the cost.

The staff also presented a variation of the first alternative, estimated at nearly $10.7 million, which would lengthen the bridge, but instead of reshaping the channel, it would clear vegetation in the creek. The option does not have a calculated benefit cost ratio because it was not studied by HDR.

The second alternative would would include the bridge work and reshaping the creek channel, as well as building levees. The estimated cost of that alternative would be about $23.4 million, and a benefit/cost ratio of 1.85.

The last new alternative involves a “regional storage” approach. The estimated cost would be $21.9 million with a ratio of 2.16, according to the report. This is a scaled back approach to one of the original alternatives presented in the spring, which would have built a series of 14 storage basins to help slow down the rate of flood waters. The new alternative would include two such basins.

“The one that seemed like it was most attractive to us is the combination alternative one,” Dunn said, referring to option that would lengthen the Highway 30 bridge, and well as reshaping the Squaw Creek channel.

Erv Klaas, professor emeritus of animal ecology at ISU and local leader for conservation causes, said the city had the chance to use FEMA money to buyout 17 businesses along South Duff Avenue in 2000. He said he argued for a wider floodway at that time.

“I’ve waited 13 years to say this, and there’s people that weren’t here 13 years ago,” he said, “and that is I told you so.”

He argued that the amount of money the city would have spent them would be less then what it is considering now.

“It’s not inappropriate to suggest that this city ought to be investing in the watershed as well as these minimal engineering solutions,” he said.

Dunn said the reshaping of the channel is a “more permanent solution” than just to clear the vegetation. He added that the “disturbed area” the city would work on would be smaller, therefore should have a smaller environmental impact. Finally, it would appear the city could qualify for FEMA funding for some of the work, Dun said.

Several members of the public spoke on Tuesday night raising concerns about how the city may deal flood mitigation.

Tom Wacha, Ward 1 councilman, said whichever path the city takes, some people will be unhappy.

“I think no matter what we decide to do, including nothing, there’s going to be people who are going to be very upset,” he said. “And I think we heard that tonight.”

The council also voted to hold a workshop to discuss regulatory alternatives at a future date.

Jami Larson, Ward 2 councilman, said that whatever regulatory steps the city takes should be in addition to whatever action it decides to take with the study options.

“I think the regulatory side would be additive to any of these suggestions,” he said.

In other business:

The council voted to agree to contract terms suggestions from city staff and directed the city attorney to draw up a contract for incentives for WebFilings, which is planning an expansion project that looks to add an additional 700 jobs to the technology company.

The Iowa Economic Development Authority has committed $5.5 million to the project, but one of the conditions would require a tax abatement incentive of $2.74 million from the city of Ames. The council did not vote on the incentive package Tuesday night, but voted on contract terms and to direct the city attorney to draw up a contract. The council plans to consider the final contract in November.

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